The Nankai 12000 series is an electric multiple unit (EMU) train type operated by the private railway operator Nankai Electric Railway in Japan on Southern Premium limited express services between Namba and Wakayamashi since September 2011. Two four-car trainsets were delivered, replacing the older 10000 series sets.

Nankai Electric Railway Co., Ltd. is a private railway in Japan, founded in 1884. The name Nankai comes from the company's routes along the Nankaidō, the old highway that ran south from the old capital, Kyoto, along the sea coast. Nankai predates all the electric railways in the Tokyo region.